(1) Field of the Invention
This invention relates generally to facsimile recording machines, and more particularly, to loop electrode arrangements on facsimile recording machines.
(2) Prior Art
Facsimile recorders are machines which receive electrical signals as input and transcribe them as visual indicia onto a moving web of paper arranged between a pair of moving electrodes. One of the electrodes is a helical band which is arranged about a revolving drum. The other electrode is an endless belt or loop which is caused to travel both a straight path and a curvilinear path along its locus of motion. The web of paper is moist and electrosensitive as it slowly passes between the electrodes, in coordination with the rotation of the helical drum electrode and the loop electrode. The locus of contact of the helical and loop electrodes sweeps along the drum while an electric current passes between the electrodes marking the paper with ions transmitted thereon from the loop electrode, thus producing the facsimile message. This ion transmission is important to the recording operation but also is the cause of gradual erosion of the marking blade, that is, the loop electrode.
To produce the messages in the most economical fashion, the loop electrodes must be adjustable toward the travelling web of paper to compensate for erosion of the electrode, instead of otherwise having to replace them frequently. An attempt to compensate for loop electrode erosion is shown in U.S. Pat. No. 2,743,990 to Leonard, wherein a plurality of arms with headed pins at their distal ends are held against the non-eroding edge of the loop by a spring arrangement. This method is not only complicated and difficult to properly maintain, it permits undesirable movement of the loop electrode such as flexing and reduces clarity of the transcribed message.
An object of the present invention is to provide a facsimile printing machine with a loop electrode which is adjustably arranged to be movable towards and away from the plane of the paper to compensate for erosion of that electrode.
Another object of the present invention is to provide a facsimile printing machine with a loop electrode having a linear portion which is actually maintained in a linear condition during interaction with its propinquitous portion of the helical electrode.
Yet another object of the present invention is to provide a facsimile printing machine with loop electrode supporting means which minimizes friction and heat buildup therewithin.
Yet still another object of the present invention is to provide a facsimile printing machine having loop electrode adjusting means with means to indicate the amount of loop electrode erosion therewith.